# [seqfan] help needed editing A175625

N. J. A. Sloane njas at research.att.com
Sat Jul 31 20:17:36 CEST 2010

```Dear Seq Fans,
Could someone please study this sequence and provide a better definition?
Max Alekseyev, if you are around, it might help if
you could ask the author in Russian exactly what the definition is.
(I assume "compound" means "composite")

Thanks, Neil

The original sequence as submitted:

Date: Wed, 28 Jul 2010 09:51:59 -0400
Subject: NEW SEQUENCE FROM submitN Alzhekeyev Ascar M A175625
Reply-to: allasc at mail.ru

%I A175625
%S A175625 11,23,31,47,59,83,107,167,179,227,263,347,359
%N A175625 N(i)=2*i+7; ((2*i+7) mod 3)> 0; (N(i) does not share on 3); 4 ^ (i+3) â‰¡ 1 (mod (2*i+7)); 4 ^ (i+2) â‰¡ 1 (mod (i+3)) N(i) - primary number
%C A175625 N(i) - primary number
%C A175625 Then number N - idle time! It is checked up to N <300 million.
%F A175625 N(i)=2*i+7; ((2*i+7) mod 3)> 0; (N(i) does not share on 3); 4 ^ (i+3) â‰¡ 1 (mod (2*i+7)); 4 ^ (i+2) â‰¡ 1 (mod (i+3))
%F A175625 N(i) - primary number
%K A175625 nonn
%O A175625 1,1
%A A175625 Alzhekeyev Ascar M (allasc(AT)mail.ru), Jul 28 2010

My edited version (which probably did not make things better):

%I A175625
%S A175625 11,23,31,47,59,83,107,167,179,227,263,347,359
%N A175625 a(i)=2*i+7; ((2*i+7) mod 3)> 0; (a(i) does not share on 3); 4^(i+3) == 1 (mod (2*i+7)); 4^(i+2) == 1 (mod (i+3)).
%C A175625 Checked up to a <300 million.
%K A175625 nonn,uned,new
%O A175625 1,1
%A A175625 Alzhekeyev Ascar M (allasc(AT)mail.ru), Jul 28 2010
%E A175625 Partially edited by N. J. A. Sloane, Jul 29 2010

An update submitted via SubmitC.html:

Date: Fri, 30 Jul 2010 07:00:11 -0400
Subject: COMMENT FROM submitC Alzhekeyev Ascar M A175625

START SUBMITC MESSAGE
Sequence: A175625
Sender: Alzhekeyev Ascar M
Address: allasc at mail.ru
Date of submission: Jul 30 2010

Description of changes, start:
Description of changes, end

cdiff, start:
*** /home/oeis/wwwfiles/sequences/tmp/tempC1.14292	Fri Jul 30 07:00:11 2010
--- /home/oeis/wwwfiles/sequences/tmp/tempC2.14292	Fri Jul 30 07:00:11 2010
***************
*** 2,7 ****
--- 2,13 ----
%S A175625 11,23,31,47,59,83,107,167,179,227,263,347,359
%N A175625 a(i)=2*i+7; ((2*i+7) mod 3)> 0; (a(i) does not share on 3); 4^(i+3) == 1 (mod (2*i+7)); 4^(i+2) == 1 (mod (i+3)).
%C A175625 Checked up to a <300 million.
+ %C A175625 30 Jul 2010
+ %C A175625 The first compound number a(i)=536870911
+ %C A175625 It is found by the user "venco" (from http://dxdy.ru)
+ %C A175625 It is interesting to notice that i+3=268435455=2^28-1
+ %C A175625 Please inform on a finding of following compound numbers in sequence.
+ %C A175625 Properties of number i+3 at exceptions (compound numbers) are very interesting
%K A175625 nonn,uned,new
%O A175625 1,1
%A A175625 Alzhekeyev Ascar M (allasc(AT)mail.ru), Jul 28 2010
cdiff, end

Also a huge b-file arrived (with a different offset).

The present version is as follows:

%I A175625
%S A175625 11,23,31,47,59,83,107,167,179,227,263,347,359
%N A175625 a(i)=2*i+7; ((2*i+7) mod 3)> 0; (a(i) does not share on 3); 4^(i+3) == 1 (mod (2*i+7)); 4^(i+2) == 1 (mod (i+3)).
%C A175625 Checked up to a <300 million.
%C A175625 The first compound number a(i)=536870911
%C A175625 It is found by the user "venco" (from http://dxdy.ru)
%C A175625 It is interesting to notice that i+3=268435455=2^28-1
%C A175625 Please inform on a finding of following compound numbers in sequence.
%C A175625 Properties of number i+3 at exceptions (compound numbers) are very interesting
%H A175625 Alzhekeyev Ascar M, <a href="b175625.txt">Table of n, a(n) for n = 2..11941610</a>
%K A175625 nonn,uned,new
%O A175625 1,1
%A A175625 Alzhekeyev Ascar M (allasc(AT)mail.ru), Jul 28 2010, Jul 30 2010
%E A175625 Partially edited by N. J. A. Sloane, Jul 29 2010

```

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